GSK pulls Tykerb filing in the US

Withdraws application for expanded approval of breast cancer drug

GlaxoSmithKline (GSK) has withdrawn a filing seeking expanded approval for its breast cancer drug Tykerb (lapatinib) in combination with Roche's Herceptin (trastuzumab) in patients with HER2-positive metastatic breast cancer who have received prior Herceptin therapy.

GSK said it took the decision after it became clear that questions raised by the Food and Drug Adminsitration (FDA) could not be addressed with the data currently available, according to Rafael Amado, head of oncology R&D at the pharma company.

At the moment the application for Tykerb is still active in the EU and other regions, but "we have decided to withdraw our application in the US with the intent to wait for ongoing studies testing the combination of lapatinib with trastuzumab", said Amado.

Data from a previous clinical trial had suggested that the combination of Tykerb and Herceptin was almost twice as effective as either agent used alone in this patient population. An FDA advisory committee had been scheduled to discuss use of the drug in this indication on July 24.

Tykerb was launched in 2007 to great fanfare as an oral alternative to Herceptin, but has struggled to make headway against its rival, in part thanks to disappointments in trials aimed at extending its indications.

In February, 2012, GSK withdrew a submission for the drug in Europe, where it is known as Tyverb, which would have allowed its use alongside paclitaxel in patients with metastatic HER2-positive breast cancer.

Meanwhile, towards the end of last year the TEACH trial of the drug as an adjuvant therapy in early breast cancer failed to show a significant improvement in progression-free survival (PFS) compared to placebo.

At the time, analysts said the data suggested Tykerb would only play a minor role in the adjuvant setting, pointing to the results of a prior study in early-stage breast cancer - called ALTTO - which showed that Tykerb monotherapy was unlikely to show non-inferiority to Herceptin in extending PFS.

Sales of Tykerb were £60m ($93m) in the first quarter of 2012, up around 15 per cent, while Herceptin pulled in 1.42bn Swiss francs ($1.44bn) over the same period.